1. Field of the Invention
The present invention relates to a technology for effectively preventing an occurrence of burrs in a casting.
2. Related Art
Relating to a casting technology, for example, Patent Reference 1 discloses a technology for designing a mold, in which a deformation amount of a product when a temperature of the product becomes a room temperature is calculated through analysis taking a temperature distribution of a mold and a temperature distribution of a product into consideration, and the mold is designed by taking the deformation amount into consideration.    [Patent Reference 1] JP-A-H07-236942
In some cases, there is seen a phenomenon in which burrs are generated in a casting.
Firstly, in a casting operation, molds are respectively expanded due to heat which is applied from a molten bath. This expansion is not uniform. Specifically, the expansion is caused to vary due to differences between shapes of respective portions of the molds, due to differences between pressures applied from the molten bath, due to differences between a mold fastening pressure of a molding machine, due to differences between amounts of heat applied from the molten bath, and the like. Owing to a partially different expansion, contact surface pressures to be applied to the mating surface of the molds cannot be uniform. As a result, in the casting operation, such portions of the mating surface of the molds as have relatively small contact pressures are opened, whereby the molten bath leaks out from such opened portions, resulting in a generation of burrs.
When such burrs are generated in the casting, there is necessary an operation of removing the burrs in a later process.
This addition of the burr removing operation leads to an increased cost of the casting. Also, in some cases, the burrs can stick to the molds. In this case, the molds cannot be properly fastened in a next casting process, which leads to further generation of burrs. When the burrs stick to the molds, there is necessary an operation to remove them. During a time for removing the burrs, the casting operation cannot be carried out. Further, since, during this time, the molds become cool, it is necessary to carry out a warming-up waste molding step again, which deteriorates a productivity of the product.